The Basics

Each year, over 2.6 million babies are stillborn1 and more than 20 million babies are born with a low birth weight putting them at a twenty-times higher risk of dying in the first year of life compared to babies born with a normal birth weight2. In high-income countries, 90% of stillbirths occur before labor starts, and only 10% occur during labor3. In these countries, the top three risk factors for stillbirth are obesity, advanced maternal age, and smoking4 – of these three, only smoking can be modified during the course of a nine-month pregnancy. That being said, several well-designed studies from high-income countries have recently identified sleeping on the back in late pregnancy as a novel modifiable risk factor for stillbirth and low birth weight!

Since 2011, multiple research studies have shown an association between sleeping on the back during late pregnancy and several adverse outcomes including stillbirth and low birth weight5-10

A study recently published in The Lancet concluded that 6% of late stillbirths could be avoided if every pregnant person slept on their side from 28 weeks’ gestation until the end of pregnancy11. To help put this in perspective, quitting smoking in pregnancy can avoid between 4-7% of stillbirths12. This novel link is biologically plausible since we know that laying on the back in late pregnancy results in the uterus and its contents compressing several major underlying blood vessels, which alters blood flow in the mother and to the baby4

The PrenaBelt™ is the first and only clinically-tested and published positional therapy device invented for pregnant women, in an effort to eliminate one of the few remaining modifiable risk factors for stillbirth and low birth weight: sleeping on the back. It has also demonstrated safety and efficacy in clinical studies around the world13-15

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  1. J. E. Lawn et al., “Stillbirths: rates, risk factors, and acceleration towards 2030,” Lancet, vol. 387, no. 10018, pp. 587–603, 2016.
  2. A. J. Wilcox, “On the importance--and the unimportance--of birthweight,” Int. J. Epidemiol., vol. 30, no. 6, pp. 1233–1241, 2001.
  3. V. Flenady et al., “Stillbirths: recall to action in high-income countries,” Lancet, vol. 387, no. 10019, pp. 691–702, 2016.
  4. J. Warland and E. A. Mitchell, “A triple risk model for unexplained late stillbirth,” BMC Pregnancy Childbirth, vol. 14, no. 1, p. 142, 2014.
  5. R. S. Cronin et al., “An individual participant data meta-analysis of maternal going-to-sleep position, interactions with fetal vulnerability, and the risk of late stillbirth,” EClinicalMedicine, vol. 10, pp. 49–57, 2019.
  6. A. Heazell et al., “Association between maternal sleep practices and late stillbirth - findings from a stillbirth case-control study,” BJOG, vol. 125, no. 2, pp. 254–262, 2018.
  7. L. M. E. McCowan et al., “Going to sleep in the supine position is a modifiable risk factor for late pregnancy stillbirth; Findings from the New Zealand multicentre stillbirth case-control study,” PLoS One, vol. 12, no. 6, p. e0179396, 2017.
  8. A. Gordon, C. Raynes-Greenow, D. Bond, J. Morris, W. Rawlinson, and H. Jeffery, “Sleep position, fetal growth restriction, and late-pregnancy stillbirth: the Sydney stillbirth study: The Sydney stillbirth study,” Obstet. Gynecol., vol. 125, no. 2, pp. 347–355, 2015.
  9. J. T. Owusu et al., “Association of maternal sleep practices with pre-eclampsia, low birth weight, and stillbirth among Ghanaian women,” Int. J. Gynaecol. Obstet., vol. 121, no. 3, pp. 261–265, 2013.
  10. T. Stacey, J. M. D. Thompson, E. A. Mitchell, A. J. Ekeroma, J. M. Zuccollo, and L. M. E. McCowan, “Association between maternal sleep practices and risk of late stillbirth: a case-control study,” BMJ, vol. 342, no. jun14 1, p. d3403, 2011.
  11. R. M. Silver, “Maternal going to sleep position and late stillbirth: Time to act but with care,” EClinicalMedicine, vol. 10, pp. 6–7, 2019.
  12. V. Flenady et al., “Major risk factors for stillbirth in high-income countries: a systematic review and meta-analysis,” Lancet, vol. 377, no. 9774, pp. 1331–1340, 2011.
  13. J. Coleman et al., “The Ghana PrenaBelt trial: a double-blind, sham-controlled, randomised clinical trial to evaluate the effect of maternal positional therapy during third-trimester sleep on birth weight,” BMJ Open, vol. 9, no. 4, p. e022981, 2019.
  14. A. J. Kember et al., “Modifying maternal sleep position in the third trimester of pregnancy with positional therapy: a randomised pilot trial,” BMJ Open, vol. 8, no. 8, p. e020256, 2018.
  15. J. Warland et al., “Modifying maternal sleep position in late pregnancy through positional therapy: A feasibility study,” J. Clin. Sleep Med., vol. 14, no. 8, pp. 1387–1397, 2018.